IFieldExpander.h

Go to the documentation of this file.

// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
#include "CoreMinimal.h"
#include "UObject/Class.h"
#include "UObject/Object.h"
#include "UObject/UnrealType.h"
 
class FObjectPropertyBase;
class FProperty;
class FStructProperty;
class UFunction;
class UStruct;
 
namespace UE::PropertyViewer
{
 
class IFieldExpander
{
public:
    virtual TOptional<const UClass*> CanExpandObject(const FObjectPropertyBase* Property, const UObject* Instance) const = 0;
    virtual bool CanExpandScriptStruct(const FStructProperty* StructProperty) const = 0;
    virtual TOptional<const UStruct*> GetExpandedFunction(const UFunction* Function) const = 0;
    virtual ~IFieldExpander() = default;
 
    UE_DEPRECATED(5.2, "CanExpandFunction is deprecated and GetExpandedFunction should be used instead.")
    virtual bool CanExpandFunction(const UFunction* Function) const
    {
        return GetExpandedFunction(Function).IsSet();
    }
};
 
class FFieldExpander_Default : public IFieldExpander
{
public:
    FFieldExpander_Default() = default;
 
    enum class EObjectExpandFlag : uint8
    {
        None = 0,
        UseInstanceClass = 1 << 1,
        RequireValidInstance = 1 << 2,
    };
 
 
    enum class EFunctionExpand : uint8
    {
        None = 0,
        FunctionProperties,
        FunctionReturnProperty,
    };
 
    virtual TOptional<const UClass*> CanExpandObject(const FObjectPropertyBase* Property, const UObject* Instance) const override
    {
        const bool bUseInstanceClass = EnumHasAllFlags(ExpandObject, EObjectExpandFlag::UseInstanceClass);
        const bool bOnlyIfInstanceValid = EnumHasAllFlags(ExpandObject, EObjectExpandFlag::RequireValidInstance);
        if (bOnlyIfInstanceValid && !Instance)
        {
            return TOptional<const UClass*>();
        }
        if (bUseInstanceClass && Instance)
        {
            return Instance->GetClass();
        }
        return Property->PropertyClass.Get();
    }
 
    virtual bool CanExpandScriptStruct(const FStructProperty*) const override
    {
        return bExpandScriptStruct;
    }
 
    virtual TOptional<const UStruct*> GetExpandedFunction(const UFunction* Function) const override
    {
        if (Function && ExpandFunction == EFunctionExpand::FunctionProperties)
        {
            return Function;
        }
        else if (Function && ExpandFunction == EFunctionExpand::FunctionReturnProperty)
        {
            if (const FObjectPropertyBase* ObjectProperty = CastField<const FObjectPropertyBase>(Function->GetReturnProperty()))
            {
                return ObjectProperty->PropertyClass.Get();
            }
        }
        return TOptional<const UStruct*>();
    }
 
    void SetExpandObject(EObjectExpandFlag InExpandObject)
    {
        ExpandObject = InExpandObject;
    }
 
    void SetExpandScriptStruct(bool bInExpandScriptStruct)
    {
        bExpandScriptStruct = bInExpandScriptStruct;
    }
 
    UE_DEPRECATED(5.2, "Use the SetExpandFunction with the EExpandFunctionType")
    void SetExpandFunction(bool bInExpandFunction)
    {
        ExpandFunction = bInExpandFunction ? EFunctionExpand::FunctionProperties : EFunctionExpand::None;
    }
 
    void SetExpandFunction(EFunctionExpand InExpandFunction)
    {
        ExpandFunction = InExpandFunction;
    }
 
private:
    EObjectExpandFlag ExpandObject = EObjectExpandFlag::None;
    bool bExpandScriptStruct = false;
    EFunctionExpand ExpandFunction = EFunctionExpand::None;
};
ENUM_CLASS_FLAGS(FFieldExpander_Default::EObjectExpandFlag);
 
} //namespace